Friction draft gear



Dec. 13, 1938. D, F, SPROUL' www FRICTION DRAFT GEAR Filed May 24, 1935 2 Sheets-Sheet 2 Patented Dec. 13, 1938 TED STATES rari-E NT z'crei-Aci:

iFRICTION DRAFT GEAR Donald?. Sproul, Chicago, Ill., assignorto Cardwell-Westinghouse Company, a 'corporation of *Delaware Application May .24, 193.5, .Serial No. .23;225

`1o claims.

This invention .relatesito draft .gears andmore gparticularl-yto 4draft gears` fof the vfriction type.

Oneof the objects of the vinvention is the pro- .vision of a new and improved draitgear "having 5;; `novel means for increasing the 'frictional 1re- -sistance to the compression :of thegear.

Another object ofthe invention isv the provision of -neW and improved Wedge mechanism for use in draft gears.

A furtherfobjectpf .the:invention is the .provi- -sion of novel l'draft .gear having new vand im- `'provedmeans for positively releasing .the wedge `mechanism .uponthe release of the gear.

Other objects of thefinvention are the provi- :sion of a new and limproved -gear that is inexpensive tomanufacture, easily fassembled, e'fcientzin operation and Whiclifis not likely to .be- :comebroken-or get .out-,of-repair.

Other vand furtheriobjects and advantages ,of -therinvention'will appear from the-followingfdes'cription ltaken in connection `Withptlie accom- .panyingdrawingsy in which:

ig. l is a horizontal section of .the-.centersills and draft gear ora railway cansh'owing the gear 4in extended expanded position;

Fig. :2 is .a section 'on the li-ne 2-'2 -.of .-Fig. l -butshowing the gear compressed;

Fig. 3is1a1sectionon the line 3-:f3tof Eig. L2;

yFig. :4 isvan endview -ofa .modified form tof the .outer .annular Wedge means Ycr ring;

Fig. 5 is a section on the line `:5-5 of Eiga;

.-Fig. 6 is aperspective View .of the inner .Wedge -.member;

Fig. 7.isaperspective'view of the intermediate wedge member;

Fig. 8 is a perspective -view'ofvtlieouter wedge .means or.ring; and

flig. 9'is -a perspective View of the outer Wedge or thrust member.

With `the increase in the capacity of railway cars, the increased capacity for draft gears to be used on these cars becemesnecessary. yBut for lack of space on the car for containing thepgear it becomes necessary to-'increase the capacity of the gear Without increasing its overall dimensions. This presents a problem diiicult of solution. High capacity gears have been proposed but .fmore or less difficulty has been-experienced in so constructing the gear thatit Will have a proper i:50 Vrelease. The present invention seeks to remedy .this-.diicultyby the provision of a high Capacity "gear having positive means operating directlyV on "the Weclgingmechanism vfor releasingsaid mechr'aIlSm. Y

:65 Referring now lto the drawings, lthe reference ill) character l0 designatesfgenerally the draftgear which isfada-pted.toV occupy the conventional draft gearpocket-l-l between `thefcenter sills I2 and :i3

of a railway-car. The draft lugs yaresl'iovvn at iM andflfand theabuier lugsat land l1. If .b desired, plates t3 and -|-9 may be inserted bel.tvvecrlrtlie 'ends ,of :the gear ll) and the draft and `bufer Jugs, respectively. The fdraft l.gear comprises a .casingfor barrel 2! VWhich is preferably :though :not necessarily circular in .cross section. -4119 #Thadraft yoke .2D surrounds .the plates and gear in the usual manner. Since the details .of the fmeans fonmounting the .gea-r *on` thecar constitutefno- .partzof the present invention'it is-not .thought necessary :to .further 'illustrate .or de- 15 scribe Ethessame.

Thezcasing ,2l is providedawith abaSeZZ which -maycomp'rise-alangel?, extendingabout the for Iviard end of the teasing i 2 l -Reinforcing ribs 2-4 frnay tbe provided for reinforcing :the fiange123. 20

The base constitutes kthe1bottcm'vvallpi the cas- 'ing22 land 4this Wall eis provided'with what for convenience :of @description lWill-:loe termed.` an in- ,Warclly :extending Vaxial @depression :25 having an axialopening.forfreceiving a boltf2l for hold- ,-25 :ing-the. gear :in .assembled relation, 1 as Will `presently appear. The inner end-of thecasing 2l is open :andisvprovided on'its 1.interior with a fric- -ticn surfaced. fSuitable :rictio-n'elements are :provicledfforffrictionally engagingthe surfacey 128 (-30 lfor-:resistingatlfle#compression of :the gear. rhese elements comprise `an inner wedge lmember 29 fhavingg'a atbasefl and an annular ,inclined `Wedging .surface 32 'facing f outwardly.

ThiswWedge memberis preferablyr-annularand ;35 .hasathesaxialropening 33 into orthrough which .fa-.reduced extension 3'4 of an intermediate Wedge :member Z35extends. The Wedge-.member-SS has the Wedge .faces .35 ,and 231, preferably annular, facing-,in .opposite directions. .Theintermediate- @140 Wedgeimemberis :also provided With an axial .opening :'38 -through-.Which extends an extension JiSaof .an outerwedge or thrust member-M. 'l'.hey vouts-,r:wedge .ori thrust `member-l l -is provided with fanzinwa'rdlylacingfannular Wedgeface 52. The :45

extension 39 :of-.thezouter'wedge member! is :hollow Iand.zoasffa.partition 43 `which isrprovided vwith-.franz axial .opening-Min axial alignment with .an opening-#5in the end Wall of the-.extension x39. The bolt Z-'lextends through the openings 50 45vand-44 and is provided with a nut G6 for en- .;gaging .the partition `I3 for holding the parts in .operative position When .thepartstars assembled, v'as will;.presenti-yfl appear.

rsuitablemeans are providedfor engaging the .55

wedging faces or inclined surfaces of the wedge members. In the form of construction shown, the inner `and outer wedging means 41 and 48 are employed for this purpose. Each of these wedging means is preferably in the form of a split ring, the inner means 41 having the inclined wedging faces 49 and the inclined wedging faces 5| which engage the corresponding wedging surfaces 32, 36 on the inner wedge member and intermediate wedge member respectively. The outer wedging means 48 likewise have the inclined wedging faces 52 and 53 facing in opposite directions which engage the wedging faces 31 and 42 of the intermediate wedge member 35 and outer wedge or thrust member 4i. Each of the wedging means or elements 41 and 48 is preferably cast with radial slots 54 (see Fig. 8) which will give them more or less resiliency.

After the casting operation, each of the wedging means is split through one of the slots 54, as shown at 55, thereby forming a split ring, as shown in Fig. 8, for permitting the expansion thereof when the gear is compressed.

Appropriate resilient means are provided for resisting the inward movement of the wedging mechanism whereby the frictional elements 41 and 48 are forced outwardly into frictional engagement with the friction surface 28 of the casing. As shown, a plurality of concentrically arranged springs 56, 51 and 58 are employed for this purpose.

The spring 55 engages the surface 3| of the wedge member 29 at one end and is seated on the end wall of the casing at its other end. This spring surrounds the springs 51 and 58 and functions to resist the inward movement of the wedge member 28 whereby upon compression of the gear, the friction element 41 will be forced into frictional contact with the friction surface 28 of the casing.

The intermediate spring 51 engages the inner end of the intermediate wedge member 35 and yieldingly resists its inward movement whereby when the gear is compressed, a wedging action Will be set up between the wedging means 48 and this intermediate wedge member. As a result of this wedging action, the wedging means 48 will be forced outwardly into frictional contact with the interior of the casing. When the gear is compressed, the frictional resistance between the outer wedge member 48 and the casing will absorb a great amount of the energy of the shock, thereby relieving the spring 56 and wedging means 29 and 41 of a considerable amount of the shock and consequently the capacity of the gear is very greatly increased without necessitating any change in the angles of the wedge faces or increasing the size or capacity of the springs. The spring 51, since it engages the inner end of the extension 34, also functions to release the wedging action between the inner wedging means 41 and the intermediate wedge member 35--that is, it releases what for convenience of description will be termed the auxiliary wedging mechanism.

The inner spring 58 functions to resiliently resist the inward movement of the outer wedge member 4I but its principal function is to release the wedging action of what may be termed the main wedging system in that it releases or loosens the wedge member 4I upon the release of the gear, and this in turn releases the annular wedge means 48. The springs all cooperate to restore the parts to normal position after release of the gear. It will thus be seen that the springs all operate independently of each other, that is, they operate in parallel.

In the operation of the device, when the gear is compressed, the spring 51 will tend to resist the inward movement of the intermediate wedge member 35 which will tend to cause the inclined surface on the wedge members to force the annular wedging means 48 outwardly into frictional engagement with the gear casing, thereby resisting further inward movement of the friction mechanism. The outer spring 56 operates simultaneously to yieldingly resist inward movement of the inner wedge member 29 which will cause a wedging action on the wedging means 41 forcing the same into frictional engagement with the inner wall of the casing.

UponA release of the gear, the inner spring 58 y will act directly upon the outer wedge or thrust member 4i for releasing this member and simultaneously the spring 51 will act directly on the intermediate member 35 for releasing the same. Since the dynamic wedging force or energy that is transmitted to the inner wedging means 41 is less than that transmitted to the outer wedge element 48, this inner wedging member may be of composition material, as shown by the wedge element 59 in Figs. 4 and 5. The composition wedge element is split as at 6I but differs from the wedge element 41 in that it is not provided with radial slots as in the other construction. The ring 59, however, may be substituted for either the friction means 41 or 48, or both, if desired.

It will thus be seen that with either types of wedging members there .are in effect what may be termed two systems of wedging mechanisms, one including the outer wedging means 48 and the other the inner wedging means 41 and that these wedging means are independently released by the springs 51 and 58 operating on the intermediate and outer wedge members respectively.

After the gear is assembled, the outer and inner wedging means if of metal may during use break up into segments along the lines of the grooves 54. The segmental wedge means will function the same as the split ring.

The capacity of the gear may be increased materially by decreasing the angles of the inclined surfaces of one or both of the wedging means 41 or 48. These .angles cannot, of course, be decreased to such an extent that they may not be released by the springs 51 and 58, as otherwise the gear will stick when compressed.

I claim as my invention:-

l. In a draft gear, a casing, wedge mechanism including inner, outer and intermediate wedge members within said casing, a plurality of springs, one'for each wedge member engaging said members, respectively, and operating independently of each other, for resisting the inward movement of said mechanism during compression and for releasing said wedge members upon the release o-f said gear, and friction means between said wedge mechanism and said casing.

2. In a draft gear, a tubular casing circular in cross section, wedging mechanism within said casing, said mechanism comprising an inner wedge member having an axial opening and an annular wedging surface facing outwardly, an intermediate wedge member having anaxial opening and an extension projecting into said first-mentioned axial opening, said last-named member having a pair of annular inclined surfaces facing in opposite directions, an outer wedge member having an annular outwardly facing wedging surface, said last-named member having an elongated reduced extension extending inwardly through said axial openings, a pair of split annular wedge rings for engaging said inclined and wedging surfaces, and outer, intermediate and inner concentrically arranged springs within said casing for engaging said inner wedging member and'said extensions, respectively, for resisting the inward movement of the wedging members and for restoring the parts to normal position upon release.

3. In a draft gear, a casing, friction mechanism within said casing, said members comprising `an annular inner wedge member having an axial opening therethrough and provided with an outwardly facing wedging surface, an intermediate wedge member having a reduced extension extending into said opening and provided with an axial aperture in alignment with said opening, said intermediate wedge member having a pair of wedging surfaces facing in opposite directions, a thrust member having an annular inwardly facing wedge surface and provided with a reduced extension extending rearwardly into said aperture, inner and outer wedge means having annular wedging faces for engaging said wedging surfaces whereby when said gear is compressed said means will be forced radially outward into frictional engagement with the interior wall of said casing, and springs engaging said inner wedge member and said projections respectively.

4. In a draft gear, a casing, .a plurality of wedging means within said casing, each having two inclined wedging surfaces facing in opposite directions, wedging members engaging said faces, and a spring for each member for resisting inward movement of said members and for positively releasing a plurality of said members upon the release of said gear, said springs operating independently of each other.

5. In a draft gear, an intermediate wedge member having two conical wedging surfaces facing in opposite directions from each other, said member having a reduced elongated axial extension having a cylindrical exterior surface, said member having an axial opening extending therethrough.

6. In a draft gear, a casing having an open and a closed end, a cylindrical depression in its closed end provided with 'an axial bore, a pair of expan'sible friction means for frictionally engaging the interior of said casing, inner, outer and intermediate wedge members for expanding said means upon the compression of said gear, said outer and intermediate wedge members having reduced concentric extensions extending inwardly and provided with axial openings, the extension of said outer wedge member being hollow and provided with a partition having an axial opening in alignment with said openings, and a bolt engaging sai-d depression and said partition for limiting the expansion of said gear and resilient means for resisting compression of said gear and for restoring the parts to normal v position after release.

7. In a draft gear, a casing, two friction shoes within said casing for frictionally engaging the inner surface of said casing, inner, outer and intermediate wedging elements engaging said shoes, one of said elements having wedging surfaces facing in opposite directions, spring means for resisting the inward movement of said shoes and wedging elements and independently engaging each of said wedging elements and operating in parallel for positively releasing the oluter wedge element.

8. In a draft gear, a casing having a friction surface, inner and outer friction shoes. for frictionally engaging the inner Wall of said casing, means for forcing said friction shoes into frictional engagement with said casing upon the compression of the gear comprising at least three wedging members, and a spring for each of said wedging members and engaging the same, said springs operating in parallel.

9. In a draft gear, a tubular casing, inner and outer friction members, each of said members having annular wedging surfaces, at least three annular wedge elements engaging said surfaces, and at least three concentric springs of substantially the same lengths within said casing engaging said wedge elements, respectively, and all of said springs being seated against one end of said casing for resisting the compression of said gear and for restoring the parts. to normal position after compression, all of said springs operating in parallel.

10. In a draft gear, a casing, at least three Wedging elements, one of which has oppositely directed wedge faces, within said casing, friction shoes engaging said elements and said casing, spring means for resisting compression of said gear and for restoring the parts to normal position after release, said means comprising a plurality of springs, one for engaging each of said elements, said springs operating in parallel and being of substantially the same length.

DONALD F. SPROUL. 

